1. Field of the Invention
This invention relates to an optical code reader for reading a 2-dimensional code affixed to an article, and more particularly to an optical code reader which can be held by hand and set close to the 2-dimensional code at the time of reading.
2. Description of the Related Art
Most supermarkets utilize bar codes printed on article labels for sales registration. The bar code represents an article code by a combination of bars linearly arranged and is optically read by a handy type bar code scanner which can be held by hand and set close to the bar code at the time of reading, for example. In recent years, the application field of the bar code has been expanded to factories, distribution industries, service businesses and the like. In these fields of application, it is necessary to represent article information other than the article code for article management by use of the bar code. Therefore, the recording capacity of the bar code tends to become insufficient. By taking this condition into consideration, 2-dimensional codes such as multi-bar codes and matrix array codes have been developed to deal with a large amount of article information.
The conventional 2-dimensional code scanner is constructed by connecting a TV camera, TV monitor and image processor to each other via cables, for example. The TV camera takes an image of the 2-dimensional code printed on an article label in the interior illumination, the TV monitor displays the image of the 2-dimensional code taken by the TV camera, and the image processor effects the image processing operation to derive article information from the 2-dimensional code image. The article information is transmitted to an external host computer connected to the image processor via a communication circuit, for example.
However, the 2-dimensional code scanner is large, heavy and expensive. Further, the operator is required to set the article label to face the TV camera without inclination and adjust the focus and aperture of the TV camera, so that the 2-dimensional code can be correctly read. This makes the start of reading delayed.
The above problem is considered to be solved by constructing the 2-dimensional code scanner such that it can be held by hand at the time of reading like the handy type bar code scanner. However, since the 2-dimensional code cannot be read when it is set partly out of the reading range, the operator must pay much more attention to the projection of the 2-dimensional code.